Fowl Play Part II -
The Shreveport urban bird experience with art and photography along with information and entertaining stories of backyard birds and nature.

Spirit of the Bird. Male Northern Cardinal in Pecan Tree Spring. Photo by Rybird from Cardinal Delights.

Banner is American Robin.

Birdsong sounds sweeter because throats filter out messy overtones The purity of birdsong is owed in large part to rapid, controlled changes in the shape of the birds' upper vocal tracts. Riede et al. (2006) showed that songbirds adjust the size and shape of their vocal tract to 'fit' the changing frequency of their song, allowing birds to produce a more whistle-like, pure-tone song. These results support a growing consensus that birds and humans make sound in much the same way although it is presumed these processes evolved independently of each other in birds and hominids. Other studies have implicated tongues, beaks, especially beak gape, in shaping the sound that birds produce. Similarly, humans move their tongues, alter the shape of their upper vocal tracts, and change the shape of their mouths when they sing, laugh, talk and groan."The bird's vocal tract, like the human vocal tract in speech, acts as a resonance filter that can control the sound coming from the mouth," said coauthor
Rod Suthers. "Beak movements during song also contribute to this filter, but are not as important as changes in the size of the internal vocal tract. Human sopranos use the same technique as the cardinal to increase the loudness of very high notes so they can be heard above the orchestra."

Photography of American Robin by Rybird from Fowl Play collection of bird photography

Above:  Robin Sense.  Despite its unassuming looks and gentle temperament, the humble red breasted robin (Erithacus rubecula) boasts a superhero-like ability. They can see magnetic fields, giving them an almost perfect sense of direction.
Just to be clear, we don’t mean that a robin can sense the Earth’s magnetic field or something like that as many other birds can, it can literally see it. In fact, if you cover a robin’s eyes with an adorably tiny blindfold, it loses this ability completely, though it will still look rather dapper. From http://www.todayifoundout.com/index.php/2014/01/robins-can-see-magnetic-fields-one-eye/

That birds' throats vibrate when they sing will come as no surprise to birdwatchers. The effect of these oscillations on the birds' sound production, however, was unknown. The acoustics of sound making are complicated. Most tones produced in nature are accompanied by a complex series of higher pitched, quieter tones called overtones. When the loudness of these overtones is high, the tone sounds more complex. Birds can control the loudness of overtones to increase the tonal purity of their song. Humans use a similar technique to produce different vowel sounds of speech by altering the shapes of their throats, the positions of their tongues and the wideness of their mouths.
"At low frequencies, the bird increases the volume of its oropharyngeal cavity and even expands the top of its esophagus," Suthers said. "These air filled structures form a single cavity with a resonant frequency that matches the main frequency of the song. This amplifies the fundamental frequency and suppresses overtones." The shape and total volume (three dimensional space, not loudness) of a singing Northern Cardinal's throat was observed and measured using Xray cinematography to observe and measure the shape and total volume (three dimensional space, not loudness) of a cardinal's throat as it spontaneously sang.
The scientists determined that note changes in birdsong were accompanied by controlled changes in the volume of the upper esophagus as well as the positions of the bird's larynx and hyoid skeleton (a Ushaped bone formation in the bird's throat). They also found that the volume of the upper esophagus goes up whenever the main tone produced by the bird goes down, and vice versa. These alterations of shape have the effect of increasing the main tone and suppressing the loudness of overtones.
From Birdsong sounds sweeter because throats filter out messy overtones at http://newsinfo.iu.edu/news-archive/3214.html

Bird - Silhouette bird art.

Anna's Hummingbird portrait.

Above: Slide show of various backyard birds taken by Rybird in Shreveport, Louisiana

Curiosity The bird Carolina Wren. Photo by Rybird

Below: IOLAIRE SUILE NA GREIN charcoal sketch of eagle by Rybird of Dabble Bird

 Eagle charcoal sketch by Rybird. From the Spartan collection of amateur fine art. See more at Spartan here: http://www.dabblebird.com/spartan.html
The white-tailed eagle is  a magnificent bird. It has the enchanting Gaelic name of Iolaire suile na grein - 'the eagle with the sunlit eye' for its striking, pale eyes.
The white-tailed eagle (Haliaeetus albicilla), is also known as the ern, erne, gray eagle, Eurasian sea eagle and white-tailed sea-eagle. It is a large bird of prey in the family Accipitridae which includes other raptors such as hawks, kites, and harriers. They are found in Eurasia, near large bodies of open water with an abundant food supply and old-growth trees for nesting. They are considered a close cousin of the bald eagle (Haliaeetus leucocephalus).
IOLAIRE SUILE NA GREIN
Eagle, with your sunlit eyes, 
Unfurl your wings, take to the skies
. Great symbol of the true and just,
Imbued with wisdom, strength, and trust.
 High upon the thermals soar,
Embodiment of Nature’s law
. First Nations’ by their will, decree,
You rule the skies with majesty
. In myth, stared down the mighty sun. 
Your voyage of destiny begun
. High above the world you soared,
Your place in legend, firm, assured. 
In clear blue skies, you hold domain,
Great King of Birds, long be your reign.

by nickthegreek ​

The Bird Buddha. Visit Dabblebird.com for my digital art.

In addition to photography I also dabble in art.  See Dabble Bird www.dabblebird.com for digital art and the Spartan collection for hands on art.

Juvenile Red Bird sketch by Rybird from Spartan collection of hands on art at Dabble Bird www.dabblebird.com

Above: Juvenile Red Bird pastel pencil sketch by Rybird from Spartan collection of hands on art at Dabble Bird www.dabblebird.com
Below: Redbird photograph  used for reference in sketching above drawing of  pastel redbird

Juvenile Redbird photo by Rybird from Cardinal Delights collection of Northern Cardinals.